Kinetic description of dioxygen binding to human hemoglobin on the 1-100 ns time scale

摘要

The results of nanosecond optical spectroscopy studies of hemoglobin geminate recombination on the 1 - 100 ns time scale are presented. Analysis of transient absorption data has shown that (ⅰ) the kinetics of O_2 recombination to hemoglobin cannot be described as a single-exponential process, and (ⅱ) the predominant part of geminate recombination takes place on the initial stage of this process. The analysis pattern as two exponentials & background yields two processes occurring during the geminate recombination on the 1 ― 100 ns time scale having the time constants of 1.2 +- 0.2 ns (64 %) and 16 +- 2 ns (20 %). However, the signal-to-noise ratio of the data does not allow to make an unambiguous differentiation between several possible non-exponential decay models.